1. Field of the Invention
The present invention relates to a mid-air recovery system and, more particularly, to a telemetry load link assembly that measures strain in a load cable between an aircraft and a recovered object and transmits a strain data signal to the aircraft for the purpose of monitoring strain and thus controlling the rate of winching on the cable.
2. Description of the Prior Art
One prior apparatus for measuring strain is a solid link upon which strain and temperature compensation gauges are firmly affixed. The gauges are electrically connected to the monitoring equipment by wires This apparatus presented several problems for the mid-air recovery aircraft, especially a helicopter.
As the object to be recovered descends by parachute, such as a satellite package or a remotely piloted vehicle (RPV), the helicopter hooks the parachute by appropriate maneuvers. Because of differences in velocities, distances, and weight, the load cable, having the load link connected therein, is unreeled from a winch drum of a hydraulic winch located in the rear of the helicopter. As the cable is unreeled, a brake is applied to the drum to stop the drum After the drum stops, the drum is reversed in direction so that the cable is wound on to the drum. During this process, great stresses are placed on the load cable which could cause it to separate and snap. The disadvantages of this apparatus is that the loose load cable along with the electrical wires can easily be entangled within the moving blades of the helicopter causing great damage; further, the electrical wires by themselves may break and also be caught within the blades. The electrical wires can also be damaged during payout since they must be attached to the load cable on the payout drum.